• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2018년도 추계학술대회
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• pp.258-259
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• 2018

미국은 직접적 잠재적 위협국에서 발사하는 탄도미사일 공격으로부터 본토를 방어하기 위해 탄도미사일 방어체계를 구축하여 운용하고 있다. 미사일 방어국(Missile Defense Agency)은 해상에서는 탄도미사일 방어체계가 탑재된 이지스함(Aegis BMD), Sea-Based X-band 레이더(SBX) 등을, 육상에서는 Ground-Based Interceptor(GBI), Early Warning 레이더, THAAD 등을 운용하고 있으며, 이에 추가하여 하와이에 탄도미사일 방어용 레이더(HDR-H)를 설치 할 예정이다. HDR-H가 전력화되면 아시아-태평양 지역에서의 탄도미사일 도발에 대한 대응 능력이 향상될 것으로 기대된다.

• 한국위성정보통신학회논문지
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• 제12권3호
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• pp.50-53
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• 2017

위성 통신은 무선 채널을 통한 광역 브로드캐스팅 특성으로 인하여 보안에 취약한 약점을 가지고 있음에도 불구하고, 위성 통신을 위한 보안 기법으로는 지상 통신에서 사용해 오던 상위 계층에서의 암호화를 제외하고 많은 방법이 알려져 있지 않다. 특히 물리계층에서의 재밍, 스푸핑 신호 공격 빈도가 증가함에 따라 이에 대한 대응 기술 개발이 중요하다고 할 수 있다. 본 논문에서는 위성통신망 보안 문제에 대해서 상위 계층과 물리 계층에서의 대응책에 대해 각각 정리하고, 사물인터넷 등의 지상망 적용을 위해 정보이론 관점에서 개발되고 있는 물리 계층 보안 기법의 최근 연구 결과에 대해 알아본다. 교차 계층 접근 방식을 포함하여, 위성 통신보안을 향상시킬 수 있는 향후 연구 방향을 제시한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권3호
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• pp.1231-1245
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• 2015

People have transferred their business model from traditional commerce to e-commerce in recent decades. Both shopping and payment can be completed through the Internet and bring convenience to consumers and business opportunities to industry. These trade techniques are mostly set up based on the Secure Sockets Layer (SSL). SSL provides the security for transaction information and is easy to set up, which makes it is widely accepted by individuals. Although attackers cannot obtain the real content even when the transferred information is intercepted, still there is risk for online trade. For example, it is impossible to prevent credit card information from being stolen by virtual merchant. Therefore, we propose a new mechanism to solve such security problem. We make use of the disposable dynamic security code (DSC) to replace traditional card security code. So even attackers get DSC for that round of transaction, they cannot use it for the next time. Besides, we apply visual secret sharing techniques to transfer the DSC, so that interceptors cannot retrieve the real DSC even for one round of trade. This way, we can improve security of credit card transaction and reliability of online business. The experiments results validate the applicability and efficiency of the proposed mechanism.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2015년도 추계학술대회
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• pp.455-457
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• 2015

제2차 세계대전 중에 최초의 탄도미사일인 V-2가 등장한 이후 발전하는 과학기술에 힘입어 미사일의 사거리, 정밀도 등이 비약적으로 향상됨에 따라 탄도미사일의 위협은 나날이 커지고 있다. 미국은 탄도미사일의 위협으로부터 자국 및 동맹국을 보호하기 위해 탄도미사일 방어체계(BMDS, Ballistic Missile Defense System)를 운용하고 있다. 센서에 의해 탐지된 탄도미사일은 요격 체계의 종류에 따라 부스트단계(Boost phase), 중간단계(Midcourse phase), 종말단계(Terminal phase) 등에서 요격하게 되며, THAAD(Terminal High Altitude Area Defense)는 고고도 종말단계에서 요격하는 체계이다. 본 논문에서는 미국의 탄도미사일 방어체계의 개념에 대해 간략히 설명하고, 그 중 THAAD의 운용 및 기술적 특징에 대해 집중적으로 조사하여 정리하였다.

• 천문학논총
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• 제38권2호
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• pp.25-36
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• 2023

Since interstellar objects like 1I/'Oumuamua and 2I/Borisov originate from exoplanetary systems, even if we do not visit the exoplanetary systems, flyby, rendezvous, and sample return missions of interstellar objects can provide clues to solve the mysteries of cosmic life phenomena such as the origin of exoplanetary systems, galactic evolution, biosignatures (or even technosignatures), and panspermia. In this paper, we review space missions for interstellar object exploration in the stage of mission design or concept study such as Project Lyra, Bridge, Comet Interceptors, and Lightcraft^TM. We also review space missions, OSIRIS-REx and NEA Scout, designed for Near Earth Asteroids(NEA) explorations, to investigate the current state of basic technologies that can be extended to explore interstellar objects in a velocity of ~ 6AU/year. One of the technologies that needs to be developed for interstellar object exploration is a spacecraft propulsion method such as solar sail, which can catch up with the fast speed of interstellar objects. If this kind of propulsion becomes practical for space explorations, interstellar object explorations will mark a new era and serve as a driving force to provide evidences of cosmic life.

• 한국시뮬레이션학회논문지
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• 제29권1호
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• pp.1-9
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• 2020

과학기술의 발전에 따라 탄도탄에 대한 위협이 나날이 증대되고 있으며, 이러한 위협에 대처하기 위한 탄도탄 요격미사일에 대한 개발이 요구되고 있다. 대탄도탄용 요격미사일의 개발을 위해서는 요격시험이 필수적이다. 시험을 통해 얻은 계측자료를 활용하여 요격미사일을 포함한 전체적인 요격 시스템의 성능을 확인할 수 있다. 그러나 요격시험 시에는 요격에 의한 파편이 발생되기 때문에 안전을 위한 민간인의 접근 통제가 필요하다. 따라서 요격시험에 앞서 요격 파편에 대한 안전구역의 신뢰도 높은 추정이 선행되어야 한다. 본 논문에서는 모델링 분석 및 시뮬레이션을 활용하여 요격 파편에 대한 안전구역을 산출하였다. 우선, 탄도탄과 요격미사일의 발사단계에서 요격까지의 전 과정에 대한 시뮬레이션을 수행하였고, 요격 시점에서의 상대 속도 및 상대 각도를 산출하였다. 이 결과를 활용하여 요격 시의 에너지를 계산하고 요격 파편의 방출속도를 산출하였다. 이후, 파편에 작용하는 항력과 중력을 고려하여 낙하 궤적을 산출하였고, 파편의 낙하 지점과 위험도를 종합적으로 고려하여 최종 안전구역을 산출하였다.

• 복식
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• 제58권4호
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• pp.128-138
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• 2008

The purposes of this study were to identify the effects of body satisfaction and self-esteem on the make-up degree of middle and high school girls. Self-administered questionnaire was used for data collection from 432 students. The results were as follows: 1) Most of middle and high school girls were in height of 161-165cm and weight of 56-60kg. Satisfaction level of middle and high school girls with their eyes was the highest and that of weight was the lowest. They showed strong intention to modify their appearances and were dissatisfied with their body. 2) Middle and high school girls' satisfaction level of home life self-esteem was the highest, but that of school life was the lowest. 3) Middle and high school girls used cosmetics to protect their skins and paid much attention to their skins. They collected cosmetics informations from their friends or family members, and began to use point make-ups from their middle school years. They purchased cosmetics at cosmetic specialty store or internet shopping mall frequently. Most of them spent less than 10,000 won monthly for cosmetics, and used lip gloss and ultraviolet rays interceptors over their face with basic cosmetics. 4) Expenditures for cosmetics, self-esteem on their appearances, and pocket money affected on make-up degree. Middle and high school girls who spent more money for cosmetics and more pocket money with higher self~esteem on their appearances showed higher degree of make-ups.

• 한국조경학회지
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• 제30권5호
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• pp.98-106
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• 2002

This study was designed to present a river model with the aim of restoring the ecosystem and improving the landscape along the urban rivers on the basin of the Namhanl river, a core life channel for the National Capital regin. The revelation of botanical status, transition trend and correlation of plants might lead to providing the urban river restoration projects and ecological river formation projects with basic data for a model of ideal aquatic ecology and landscape. The outcomes of this study could be summed up as follows: 1. The plant communities of river flora found on the basin of the Namhan river could be categorized largely into 39 plant communities 2. Most diverse plants were distributed in the rivers lower reaches such as Unsim-ri where the protected zone of Paldang reservoir for city water borders the body of Jodae swamp where natural streams flow nearby. 3. One of the greatest threats to the biomass of the River Namhan is that the communities of such invasive alien plants as Panicum dichotomiflorum and Ambrosia artemisiifolia var. elatior dominate most parts of the area, a fact that has resulted in a reduced variety of plants and will, sooner or later, be likely to cause an ecological imbalance in the hitherto healthy Aquatic plant life. It is highly advisable to gradually diversify the species of trees and to return the plants bark to their original state since, besides the naturalized plants, plantations afforested with Erigeron canadensis and Erigeron annuus stocks in buckwheat field, Robinia Pseudo-accacia in riverside forest, Pinus rigida in terrestrial forest on the river basin and Larix leptolepis are anticipated to act as interceptors of normal migrations of the fluvial and terrestrial ecosystems. Finally, it seems also desirable to continue to explore the relationship between fluvial and terrestrial ecologies with the purpose of building up a model of natural streams in urban areas based on the surveyed factors for plant life, soil and landscape and, moreover, on the forecasting for overall influences derived from the rotation upon the ecosystem.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2015년도 추계학술대회
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• pp.433-435
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• 2015

제우스가 딸 아테나에게 준 방패에서 유래한 이지스 전투체계(Aegis Combat System)는 미 해군이 개발한 함정 전투체계로, 이지스 전투체계가 탑재된 이지스함은 미 해군의 주력 수상 전투함으로 운용되고 있다. 특히 AN/SPY-1 위상배열 레이더의 대공표적 탐지 능력과 전투체계의 우수한 표적 관리 및 지휘통제 능력, SM 계열 요격 미사일 등을 이용한 대공전 분야에서 현존하는 세계 최고의 함정으로 알려져 있다. 1983년대에 처음 실전 배치된 타이콘데로가함(USS Ticonderoga) 이후 미 해군은 지속적으로 이지스 전투체계 및 함형을 발전시켜왔고, 기존의 함정 또한 현대화 사업을 통해 성능을 개량하고 있다. 본 논문에서는 미 해군 이지스함의 역사와 이지스 전투체계의 발전 현황 및 특징을 조사하고, 우리 해군이 벤치마킹해야 할 교훈을 도출하였다.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2008년 영문 학술대회
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• pp.330-339
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• 2008

Ground-based interceptors(GBI) comprise a major element of the strategic defense against hostile targets like Intercontinental Ballistic Missiles(ICBM) and reentry vehicles(RV) dispersed from them. An optimum design of the subsystems is required to increase the performance and reliability of these GBI. Propulsion subsystem design and optimization is the motivation for this effort. This paper describes an effort in which an entire GBI missile system, including a multi-stage solid rocket booster, is considered simultaneously in a Genetic Algorithm(GA) performance optimization process. Single goal, constrained optimization is performed. For specified payload and miss distance, time of flight, the most important component in the optimization process is the booster, for its takeoff weight, time of flight, or a combination of the two. The GBI is assumed to be a multistage missile that uses target location data provided by two ground based RF radar sensors and two low earth orbit(LEO) IR sensors. 3Dimensional model is developed for a multistage target with a boost phase acceleration profile that depends on total mass, propellant mass and the specific impulse in the gravity field. The monostatic radar cross section (RCS) data of a three stage ICBM is used. For preliminary design, GBI is assumed to have a fixed initial position from the target launch point and zero launch delay. GBI carries the Kill Vehicle(KV) to an optimal position in space to allow it to complete the intercept. The objective is to design and optimize the propulsion system for the GBI that will fulfill mission requirements and objectives. The KV weight and volume requirements are specified in the problem definition before the optimization is computed. We have considered only continuous design variables, while considering discrete variables as input. Though the number of stages should also be one of the design variables, however, in this paper it is fixed as three. The elite solution from GA is passed on to(Sequential Quadratic Programming) SQP as near optimal guess. The SQP then performs local convergence to identify the minimum mass of the GBI. The performance of the three staged GBI is validated using a ballistic missile intercept scenario modeled in Matlab/SIMULINK.